How can I make a DIY bitter spray for cats to deter them from scratching furniture?

To make a DIY bitter spray for cats to deter them from scratching furniture, mix equal parts of white vinegar and water in a spray bottle. Add a few drops of citrus essential oil for a stronger scent. Shake well before use and spray on the furniture where your cat likes to scratch. The bitter taste and strong scent will discourage your cat from scratching in that area.